What is the difference between bit rate and baud rate? Give an example where both are same. Give an example where they are different.

 

Difference Between Bit Rate and Baud Rate:

- Bit Rate refers to the number of bits transmitted per second (bps).

  - It represents the amount of data being transmitted.

  

- Baud Rate refers to the number of signal units (symbols or changes) transmitted per second.

  - It represents how many times the signal changes per second, not necessarily the number of bits transmitted.

The key difference is that each signal change (symbol) can represent more than one bit. Therefore, the baud rate and bit rate are only the same when each symbol carries exactly one bit. When a symbol carries more than one bit, the bit rate will be higher than the baud rate.

Example Where Both Are the Same:

- Binary signaling (1 bit per symbol):

  - In simple binary signaling (e.g., 0 and 1), each symbol carries one bit of information.

  - Example: A system that uses two symbols (0 and 1) and has a baud rate of 1000 symbols per second will also have a bit rate of 1000 bits per second.

  - Baud Rate = 1000 baud, Bit Rate = 1000 bps.

Example Where They Are Different:

- Multi-level signaling (more than 1 bit per symbol):

  - When more bits are packed into each symbol using modulation techniques like Quadrature Amplitude Modulation (QAM), each symbol can represent multiple bits.

  - Example: In 16-QAM, each symbol represents 4 bits (since 16 levels = 2⁴ = 4 bits per symbol).

  - If the baud rate is 1000 symbols per second, and each symbol carries 4 bits, the bit rate would be:

    - Baud Rate = 1000 baud, Bit Rate = 1000  4 = 4000 bps.

In this case, the bit rate is four times the baud rate.